BKE_key: add BKE_key_from_id helper functions

source/blender/blenkernel/BKE_key.h

@@ -65,6 +65,8 @@ float *BKE_key_evaluate_object_ex(
 float *BKE_key_evaluate_object(
         struct Object *ob, int *r_totelem);
 
+struct Key     **BKE_key_from_id_p(struct ID *id);
+struct Key      *BKE_key_from_id(struct ID *id);
 struct Key     **BKE_key_from_object_p(struct Object *ob);
 struct Key      *BKE_key_from_object(struct Object *ob);
 struct KeyBlock *BKE_keyblock_from_object(struct Object *ob);

source/blender/blenkernel/intern/key.c

@@ -1392,24 +1392,49 @@ float *BKE_key_evaluate_object(Object *ob, int *r_totelem)
 	return BKE_key_evaluate_object_ex(ob, r_totelem, NULL, 0);
 }
 
+Key **BKE_key_from_id_p(ID *id)
+{
+	switch (GS(id->name)) {
+		case ID_ME:
+		{
+			Mesh *me = (Mesh *)id;
+			return &me->key;
+		}
+		case ID_CU:
+		{
+			Curve *cu = (Curve *)id;
+			if (cu->vfont == NULL) {
+				return &cu->key;
+			}
+			break;
+		}
+		case ID_LT:
+		{
+			Lattice *lt = (Lattice *)id;
+			return &lt->key;
+		}
+	}
+
+	return NULL;
+}
+
+Key *BKE_key_from_id(ID *id)
+{
+	Key **key_p;
+	key_p = BKE_key_from_id_p(id);
+	if (key_p) {
+		return *key_p;
+	}
+
+	return NULL;
+}
+
 Key **BKE_key_from_object_p(Object *ob)
 {
-	if (ob == NULL)
+	if (ob == NULL || ob->data == NULL)
 		return NULL;
 
-	if (ob->type == OB_MESH) {
+	return BKE_key_from_id_p(ob->data);
-		Mesh *me = ob->data;
-		return &me->key;
-	}
-	else if (ELEM(ob->type, OB_CURVE, OB_SURF)) {
-		Curve *cu = ob->data;
-		return &cu->key;
-	}
-	else if (ob->type == OB_LATTICE) {
-		Lattice *lt = ob->data;
-		return &lt->key;
-	}
-	return NULL;
 }
 
 Key *BKE_key_from_object(Object *ob)